The representation of coupling interactions in the Material Properties Open Database (MPOD)

International audience; The Material Properties Open Database (MPOD, http//mpod.cimav.edu.mx) is a functional element of the web-based open databases system linked with crystallography. MPOD delivers single-crystal tensor properties in several representations, ranging from numerical matrices to 3D printing. Longitudinal moduli surfaces can be displayed in computers as well as in smart cell phones. Properties are stored as '.mpod' files. IUCr formatting standards (CIF) are followed. The original published paper containing the data is cited. Structural and experimental information is also registered and linked. 'Coupling properties', say piezo-effects and magnetoelectricity, represent interactions linking different subsystems in a material. Currently, piezoelectricity occupies a significant fraction of cases in MPOD. The implications of crystal symmetry in piezoelectricity are systematically taken into account. Matrices' elements and longitudinal moduli surfaces are checked for consistency with the Neumann principle. The inclusion of magnetoelectric axial tensors introduces exciting features into MPOD

Developments and applications of the OPTIMADE API for materials discovery, design, and data exchange

The Open Databases Integration for Materials Design (OPTIMADE) application programming interface (API) empowers users with holistic access to a growing federation of databases, enhancing the accessibility and discoverability of materials and chemical data. Since the first release of the OPTIMADE specification (v1.0), the API has undergone significant development, leading to the upcoming v1.2 release, and has underpinned multiple scientific studies. In this work, we highlight the latest features of the API format, accompanying software tools, and provide an update on the implementation of OPTIMADE in contributing materials databases. We end by providing several use cases that demonstrate the utility of the OPTIMADE API in materials research that continue to drive its ongoing development

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

Functional parameters indicative of mild cognitive impairment: a systematic review using instrumented kinematic assessment

Background: Patients with mild cognitive impairment (MCI) experience alterations of functional parameters, such as an impaired balance or gait. The current systematic review set out to investigate whether functional objective performance may predict a future risk of MCI; to compare functional objective parameters in patients with MCI and a control group; and to assess changes in these parameters after different physical activity interventions. Methods: Electronic databases, including PubMed, AMED, CINAHL, EMBASE, PEDro and Web of Science as well as grey literature databases, were searched from inception to February 2020. Cohort studies and Randomized Controlled Trials (RCTs) were included. The risk of bias of the included studies was assessed independently by reviewers using quality assessment checklists. The level of evidence per outcome was assessed using the GRADE criteria. Results: Seventeen studies met inclusion criteria including patients with MCI. Results from RCTs suggested that gait speed, gait variability and balance may be improved by different physical activity interventions. Cohort studies showed that slower gait speed, above all, under Dual Task (DT) conditions, was the main impaired parameter in patients with MCI in comparison with a Control Gorup. Furthermore, cohort studies suggested that gait variability could predict an incident MCI. Although most of included cohort studies reported low risk of bias, RCTs showed an unclear risk of bias. Conclusions: Studies suggest that gait variability may predict an incident MCI. Moreover, different gait parameters, above all under DT conditions, could be impaired in patients with MCI. These parameters could be improved by some physical activity interventions. Although cohort studies reported low risk of bias, RCTs showed an unclear risk of bias and GRADE criteria showed a low level of evidence per outcome, so further studies are required to refute our findings

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

Chihuahua, Tierra de Cristales 2014, Año Internacional de la Cristalografía

Se presenta la definición de cristal, su diferencia respecto del vidrio, y la historia del descubrimiento de la difracción de rayos X, cuyo centenario ha motivado la declaración del año 2014 como Año Internacional de la Cristalografía. Se muestran los experimentos de Max von Laue, así como de William H. y William L. Bragg y se explican mediante la analogía con la difracción de la luz visible. Se exhiben las estructuras cristalinas de numerosos materiales importantes para el ser humano, su evolución y su desarrollo. Se exponen qué son los monocristales y los policristales, así como las diferentes estructuras cristalinas del carbono. Se explica cómo el progreso de la cristalografía, junto con la mecánica cuántica, han conducido a la tecnología moderna de la computación y las comunicaciones, comenzando desde el diodo semiconductor y el transistor hasta los modernos microprocesadores. Se describen la ferroelectricidad y la superconductividad y sus aplicaciones. Por último, se divulgan ejemplos del desarrollo moderno de la nanotecnología. Se explica cómo un monocristal nace y crece a partir de un nanocristal, para terminar con la demostración de que Chihuahua es Tierra de Cristales por la presencia de la Cueva de los Cristales Gigantes en Naica. Abstract It is presented the definition of a crystal, the differences with glass, and the history of the discovery of the X-ray diffraction, whose centenary has led to the declaration of 2014 as the International Year of Crystallography. The experiments of Max von Laue, as well as of William H. and William L. Bragg are described and explained using an analogy with the diffraction of visible light. The crystal structures of several important materials for human kind, their evolution and development are exhibited. The questions of what are single crystals and what are polycrystals are answered, as well as the different crystal structures of carbon atoms can form. The process of how Crystallography, along with quantum mechanics have led to the modern technology of computing and communications is detailed starting from semiconductor diodes and transistors up to the advent of modern microprocessors. The ferroelectric and superconductor materials are described, and their applications. Finally, examples of modern development due to nanotechnology are disclosed. The explanation of how a single crystal is born and grows from a nanocrystal is provided, finishing with the demonstration that Chihuahua is a land of crystals because of the presence of the Giant Crystals Cave at Naica. Keywords: Naica, crystallography, crystal structure, selenite

The Global and Local Symmetries of Nanostructured Ferroelectric Relaxor 0.94(Bi0.5Na0.5)TiO3 0.06BaTiO3

Paper presented at the International Workshop on Relaxor Ferroelectrics (IWRF-2013) that took place in Ioffe Institute (St. Petersburg, Russia) during 1-6th July 2013.Novel submicrometer-grained 0.94(Bi0.5Na0.5)TiO3 ¿ 0.06 BaTiO3 ceramic, prepared from nanopowder by a combination of hot-pressing and recrystallization, is investigated by high-resolution synchrotron x-ray diffraction and x-ray absorption near-edge spectroscopy (XANES). The simplest and best-fitting Rietveld refinement of the performed wide-Q diffraction experiment corresponds to a three-phase system formed by a ferroelectric rhombohedral R3c phase, a globally cubic P-3mm phase and a small amount of nanosized (~12 nm) quasi-cubic phase. The globally cubic phase and the nanosized one built up a complex, nanostructured, configuration that accounts for the reported dielectric relaxor behavior. XANES reveals that the departures from centro-symmetry at the unit cell scale for the precursor powder and for the sintered ceramic are practically the same

Naica’s giant crystals: Deterioration scenarios

The Cave of Giant Crystals of Naica (Chihuahua, Mexico) is a world geological treasure worth to be preserved. These crystals of up to 12 m in length are made of selenite, the macrocrystalline variety of gypsum (CaSO4·2H2O). They have grown for thousands of years until the cave was dried, which allowed the cave and the crystals to be accessible, but exposed their surfaces in contact with air. Gypsum crystals are fragile because of their trend to dehydrate, the possible replacement to CaCO3 upon reactions with atmospheric CO2 as well as their intrinsic mechanical properties. Several laboratory experiments, designed to study the deterioration of selenite crystals under different artificial atmospheric conditions, are presented. Four atmospheric compositions rich in CO2, CH4, NOx, and air were tested for 1 year at temperatures of 25 and 60 °C and in either liquid or gaseous environments. The surface evolution was monitored by optical microscopy, infrared spectrometry, and grazing incidence X-ray diffraction with two-dimensional detectors. Surface alteration and dissolution in a water environment were observed in short exposition times, as well as the formation of bassanite (CaSO4·1/2H2O). Neither anhydrite nor calcite was detected. The gaseous environment constituted the most detrimental conditions to the gypsum crystals integrity.The authors would like to acknowledge Consejo Nacional de Ciencia y Tecnologia (grant number 183706); Industrias Peñoles for the support given to the experiments; A. Reyes-Rojas, D. Burciaga-Valencia, and E. Guerrero-Lastarjette for their continuous support in the realization of this project; and B. Aldea-Ballano and the team of the Chemical and Physicochemical Testing Unit in Instituto Eduardo Torroja de Ciencias de la Construcción in Madrid. The authors especially thank J. M. García-Ruiz for the suggestions of some experiments. Part of the experiments was performed (as part of Proposal No. 3939) at the Stanford Synchrotron Radiation Lightsource (SSRL), a Directorate of SLAC National Accelerator Laboratory and an Office of Science User Facility operated for the U.S. Department of Energy, Office of Science, by Stanford University.Peer reviewe